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mouth structure

...as dense as some rocks. In almost all beaked whales, functional teeth are limited to one or two pairs present only in the lower jaw, and these usually erupt through the gums only in the male. In the
strap-toothed whale (
M. layardii), these two tusklike teeth are remarkable in that they curve upward out of the mouth, holding the jaws partially shut. Shepherd’s beaked whale (
Tasmacetus...